The objective of this research was to examine whether the United States and Canada have successfully implemented their Great Lakes Water Quality Agreement and to identify the factors determining the continuation of any injury to human health from pollution of the boundary waters. The Agreement was first negotiated in 1972 as part of the legitimation of the social unrest of the 1960s and gave special responsibilities to the International Joint Commission to advise the Parties of problems of water quality. It has been subject to periodic review and occasional renegotiation and amendment. Specifically, the Agreement was renegotiated in 1978 to address the health effects from the imperceptible exposures to persistent toxic substances. Though extensive scientific evidence of continuing injury to health from persistent toxic substances has been available, there has been a consistent pattern of deliberate failure by the authorities to report the injury and to implement many of the remedial provisions contained in the Agreement. The thesis claims that the failure of the International Joint Commission to advise the Parties of the new information about the injury to health and the failure of the Parties to act upon the information when it was obtained from other sources constituted dereliction of duty. While synthesis of the science linking the pollutant-induced injury to specific causal agents was necessary to provide an empirical measure of the failure to implement the Agreement, consideration of the social, economic and political aspects was needed to provide a sufficient explanation for the failure of the International Joint Commission to inform and of the authorities to act. There have been active attempts to use diversionary reframing of the Agreement, based on a multi-causal ecosystem theory proposed by fisheries ecologists, to attenuate the risk message and transform the Great Lakes Water Quality Agreement into a more inclusive and less focused agreement on restoring ecosystem integrity. This has been welcomed by industry and governments as a means to remove the focus from addressing the unresolved dangers of persistent toxic substances through costly remedial actions. The International Joint Commission undermined its credibility when it recommended ‘sunsetting’ the use of chlorine in chemical manufacturing. The Parties failed to use a precautionary approach to prevent the commercial introduction of new persistent toxic substances, such as the brominated flame retardants. Since the 1980s, the economic politics of the two nations have been profoundly influenced by neo-liberalism and one of the consequences has been the removal of environmental health as a priority from the respective political agenda. Advisory bodies seem to have been captured not only by the prevailing neo-liberalism but also by corporate interests and these factors seem to underlie the reluctance to report the injury to health from exposures to persistent toxic substances. Though there were many different health endpoints affected by exposures to water pollutants in the Great Lakes, the thesis concentrated on the evidence of neuro-teratogenic effects. The adequacy of the implementation of the Agreement during the past thirty-three years was tested by using Health Canada data on cerebral palsy hospitalisation to evaluate whether there were indications of previously undetected outbreaks of congenital Minamata disease in human populations in Canadian Great Lakes communities potentially exposed to methyl mercury from natural sources or from historic industrial uses of mercury. The uncertainties in the apparent association that was found were reduced by the application of Hill’s guidelines. While these findings indicated both the need for further multi-disciplinary research to locate and diagnose the victims and for a precautionary approach to the consumption of Great Lakes fish, they also indicated that, for more than three decades, health authorities have not diligently implemented the Agreement. The inclusion of the social, economic and political considerations in the forensic audit has revealed the dangers inherent in any renegotiation of the Great Lakes Water Quality Agreement.